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    <meta charset="UTF-8">
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    <title>Document</title>
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<body>
    <script>
        function Star(uname,age){
            this.uname = uname;
            this.age = age;
            //构造函数中的this指向实例对象
        }
        var that;
        Star.prototype.sing = function(){
            console.log('我会唱歌');
            that = this;
        }
        var ldh = new Star('刘德华',19);
        ldh.sing();
        console.log(that === ldh);
            //原型对象里面的this指向的是实例对象
    </script>
</body>
</html>